The present invention relates to a seal for a window in a motor vehicle, and in particular to a windshield seal for use in a large vehicle in which there may be flexing of the structure defining a window opening.
It is well known to utilize rubber seals to create a somewhat flexible support and provide a sealing interconnection between a glass pane and the relatively flexible body structure of a motor vehicle surrounding a windshield or other fixedly mounted window in a motor vehicle.
As shown in Eichner U.S. Pat. No. 2,189,138, a conventional seal for a windshield may include a rubber strip defining pair a of oppositely facing channels which receive, respectively, a margin of a body panel or the like defining a window opening and a margin of a pane of glass. A locking strip fits in a groove defined in the seal to keep the seal in place.
A somewhat similar seal structure is shown also in Isbell U.S. Pat. No. 2,770,487.
When the structure of a motor vehicle surrounding a large fixed window such as a windshield or rear window is even slightly flexible, as in the case of the window openings of the cab of a large truck, flexure may cause significant movement of surrounding body panels relative to a window pane. Relative movements of up to 3 mm may occur, resulting in relaxation of sealing pressure between a window pane and a conventional rubber seal""s critical surface. When such a motor vehicle is operated on uneven surfaces, leakage may occur around a window pane if such a conventional seal is flexed and water enters into the channel surrounding the glass pane. With repeated cycles of flexure, repeated small amounts of water can enter into the channel surrounding the pane of glass and travel around the margin of the pane of glass and then be squeezed from the channel of the seal into the interior of the vehicle. Such xe2x80x9cpumpingxe2x80x9d of water into the interior of a motor vehicle can result in significant costs, not only for repair of water-damaged interior materials, but also in terms of loss of use of the vehicle, if a commercial vehicle has to be taken out of service to accomplish repair of such a leaking condition.
In the past, repair of leaky windshield seals has often been accomplished by the use of a flexible adhesive sealant cement to create a better seal than can be obtained by only the elastic pressure of the rubber against the surfaces concerned. While this can provide a watertight seal, if a windshield sealed in this manner is damaged and must be replaced, replacement requires a significant amount of time because of the extra labor involved in dealing with the adhesive cement. Where an adhesive cement sealant is used to install a replacement windshield the motor vehicle may well be unavailable for commercial use for 48 hours to provide ample time for the adhesive material to cure properly. Since time utilized in such repair represents time when the motor vehicle is unavailable to generate revenue, not only is it desirable to provide a windshield seal which is effective in excluding water from the interior of the motor vehicle in which it is used, but it is also important to provide a seal which allows rapid and efficient replacement of the glass when that becomes necessary. It is therefore desirable to provide a window seal which is effective without the use of an adhesive sealant material in addition to the mechanical action of a glass-supporting seal assembly.
Window seals have previously been made of synthetic rubber materials such as ethylene-propylene diamene monomer (xe2x80x9cEPDMxe2x80x9d), or other rubber-like materials, which typically cure chemically after being manufactured and have a significant weight. It is desirable, however, for a seal to be manufactured of a material which is somewhat lighter, in order to reduce the total weight of a motor vehicle, and it is also desirable to make a seal of a material which is easily molded or extruded, yet which has the necessary strength, flexibility and resiliency.
The present invention provides an answer to some of the aforementioned shortcomings and disadvantages of the prior art window seal structures by providing a seal that is watertight despite significant window pane movement relative to the structure defining a window opening in a motor vehicle. Broadly, the present invention provides a flexible seal made of an elastomeric material, defining a channel receiving a margin of a pane of a window, and including a flexible, elastic sealing lip, located near the channel. The lip extends toward and continuously presses against the pane at a short distance away from an edge of the channel despite pane movement relative to the surrounding structure.
In one preferred embodiment of the invention a lip extends from a shoulder of an exterior wall that defines a channel in which a margin of a pane of a window is received and supported, and a narrow sealing surface along an outer margin of the sealing lip is pressed against an outer surface of the pane as a result of the elastic deformation of the lip by the pane.
In one preferred embodiment of the invention a first or outer channel is provided in an outer margin of an elastomeric main member of a seal, to receive a portion of a surrounding structure defining a window opening in a motor vehicle body, and a glass-holding channel is located opposite the outer channel in a generally coplanar arrangement, with the sealing lip extending from a shoulder of a wall defining the glass-holding channel.
In one preferred embodiment of the invention, a locking strip is engaged in a corresponding groove to keep the exterior walls of both the outer, or body panel-receiving, channel and the glass-holding channel properly located with respect to each other and with respect to the margins of a surrounding body structure defining a window opening and of a pane of the window being sealed. The locking strip thereby also helps to support the root of the sealing lip, urging the lip and, particularly, its sealing surface, into contact against an outer surface of the window pane.
In a preferred embodiment of the invention, when the main member of the seal is in a relaxed condition the lip extends curvingly toward the interior side of the main member, so that when a pane of glass is installed within the glass-holding channel the lip is elastically deformed, and a narrow sealing surface near an outer margin of the lip is elastically pressed against an outer surface of the window pane.
In a preferred embodiment of the invention the lip has a length from its root to its outer margin or tip that is at least two to four times the thickness of the lip so that the lip is resiliently flexible.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.